How to avoid 1 times scan Code multiple entry information, or multiple clicks to determine multiple redemption?

Hello everyone, I am doing the development.
As the question: in the sweep code when live Click button Redemption, how to avoid multiple prizes.
2 Types of offline activities: 1 sweep QR code 2 Click the Claim button.

There was no problem at the time of the test (small company, just a few people testing).
This is caused by a user network problem, a program vulnerability, or a logical problem ....
Because there are 1 users with 9 timestamps of the same record ....
I'm using the Ajax pass value now.

Reply content:

Hello everyone, I am doing the development.
As the question: in the sweep code when live Click button Redemption, how to avoid multiple prizes.
2 Types of offline activities: 1 sweep QR code 2 Click the Claim button.

There was no problem at the time of the test (small company, just a few people testing).
This is caused by a user network problem, a program vulnerability, or a logical problem ....
Because there are 1 users with 9 timestamps of the same record ....
I'm using the Ajax pass value now.

You this is the form of duplicate submission, there will be a problem, the Web page can be clicked after the JS Disable button, after the successful submission of the end of the ban, reply click. Two-dimensional code is the same truth

Each user has OpenID, according to OpenID, users open the page when the first query interface, whether the database has data, if there is, to find out, display to the page, an identity bit has been redeemed, if you have a limit on the number of prizes, then the number of restrictions can be.

It's not easy. How many times do you make a mark when you click on the lottery to return the result so again, because no number of times is naturally rejected.

Record redemption information on it, OpenID is different.

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